Insulation to prevent ice dams


  #1  
Old 02-03-04, 09:58 AM
dennpars
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Insulation to prevent ice dams

We have a 1940ish bungalow that had developed some ice dams and we got a little bit of water into the basement because of it. I've learned that this is caused by heat being lost out of the house into the attic. My goal is to prevent ice dams from forming altogether on the roof.

Ventilation should be good, we just had a new roof put on this past fall and they installed 6 canister vents on the east side of the house and one on the west side.

Looking at the insulation on the knee wall it looks like the original insulation, a white, cottony substance, very thin and light between the 2X4 construction.

I'm contemplating replacing this insulation with R13, but what other things do I need to look for to insulate? I'm not sure what's under the floor boards in the attic. What about insulation from the upstairs ceiling to the peak?

What about the attic access doors themselves? In wall mounted on each side of the room. Simple doors, 4 feet high, three feet wide.

I guess I'm wondering if this is too big a project to take on myself and if I should hire professionals with more know-how to do the job right. It all seems a little overwhelming to me right now.

Thanks in advance

Dennis
 
  #2  
Old 02-03-04, 11:17 AM
Ed Imeduc's Avatar
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Lightbulb Ice dams

New roof didnt they put a ice shield under the starter rows of shingles? Vents in roof 6 in the east side why not 6 in the west also. But do you have vents in the over hang of the home so air can get in there? You cant have any insulation touching the roof boards at all. ED
 
  #3  
Old 02-03-04, 11:51 AM
dennpars
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Yes, roofing contract calls out ice shield on the first few rows of shingles, although I haven't verified that it is there, I don't have any reason to believe that they did not install it. My conversation with the roofer after the dam occured leads me to believe that ice is getting into the house via some other route than the roof proper. He suggested how the gutter connects to the house or something.

The canisters were done this way to maintain "curb appeal" by eliminating canisters on the road side of the house. This is a pretty small house, I think the roof is 25 to 30 feet long, so this number of canisters seems adequate to me. In any event, the ice dam I'm having the problem with is on the east side of the house with the six canisters.

I'll have to verify the insulation in the attic, but I'm pretty sure there is no insulation touching the roof at all, at least from the eaves to the point where the knee wall contacts the roof.

Thanks for the help

Dennis
 
  #4  
Old 02-03-04, 12:05 PM
Ed Imeduc's Avatar
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Do you have vents in the over hang of the home Old vent set up you should have 1sq ft for every 150 sq ft of attic. !/2 in and 1/2 out ED
 
  #5  
Old 02-03-04, 01:35 PM
dennpars
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I'll have to verify this, the house is on the other side of the state, so I don't have quick access to it.

I'll check all of this out when I get there this weekend.
 
  #6  
Old 02-03-04, 09:02 PM
pagerboy
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Shouldn't there be vents in the soffit and then some up at the top?

There must be too much heat loss so that it is melting the snow.
 
 

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